2. Chocolate and butter melt in water;
3. Add whipped cream and stir well;
4. Add an yolk to the egg. After adding fine sugar, beat it with a manual whisk to make it bigger (don't send it away);
5. Pour the egg paste into the chocolate paste and stir well;
6. After adding a little rum, sift in the flour and stir well;
7. Pour the stirred batter into a medium paper cup, about 7 minutes full;
8. Preheat the oven at 200 degrees, in the middle layer, for 6-8 minutes;
9. After baking, cool until it is not hot. Tear off the paper cup and put it upside down on the plate. Sprinkle a proper amount of powdered sugar on the surface.